The present invention relates to a railroad superstructure supporting framework, with reinforced concrete prefabricated elements, and a prefabricated reinforced concrete platform therefor.
Prior railroad superstructure supporting frameworks comprised pre-compressed reinforced concrete sleepers supported on a ballast of crushed stones.
Such a conventional system has a great use flexibility and can exploit the natural adaptability of the crushed stones to unexpected stresses.
On the other hand, this system requires frequent maintenance operations, with a consequent slowing down and interruption of the train traffic, in particular in a case of a mixed type of traffic with a high variability of load per axle, speed and features.
Moreover, such a conventional system provides for the use of broad building and operation tolerances, which are not compatible with the requirement related to the use of high speed trains.
Because of this reasons, in these last years there have been experimented, in several countries, different types of supporting frameworks, for example including sleepers directly applied to a foundation made of reinforced concrete.
Actually, in these alternative systems the maintenance requirements are very reduced; however, possible breakages of the structure and components thereof require very expensive and delicate repairing operations, for re-building in situ the broken concrete foundation and for replacing the degraded bedding materials. Thus, a possible replacing of prefabricated components, if required, is such as to nullify the provided advantages.
In fact, in these supporting frameworks in which the sleepers are directly supported on concrete material, it is not possible to exploit the natural adaptability of the crushed stones to unexpected stresses and, moreover, these systems do not posses the use flexibility characterizing the conventional supporting framework system.
Because of the above mentioned reasons, the attempts to design new systems have not provided an acceptable solution, and the broad range of different approaches attempted through the overall world, sometimes on a large scale, is an evident proof of this.
In this connection it should be pointed out that short duration and small scale experiments in this field do not provide a significative information and this slows down the development time of new technologies.
On the other hand, there subsists a great need of a railroad superstructure supporting framework which has a better geometric configuration, a greater reliability and duration and, moreover, can be easily fitted to existing railroads while reducing the environmental impact especially with respect to the noise and vibrations.